Telephone muffler



T. BENEDICT.

TELEPHONE MUFFLER.

APPLICATION FILED 1mm, \922.

1,419,606. PatentedJune13, 1922.

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,i? ii UNITE stares PTENT ori ice.

THEOIBALD BENEDICT, OF NEW YORK, N. Y., ASSIGNOB, OF ONE-THIRD TO JACK DIETRICH, OF NEW YORK, N. Y.

TELEPHONE MUFFLER.

Specification of Letters Patent. Patent d J 13 192 Applicationfiled January 27, 1922. Serial No. 532,110.

To all whom it may concern citizen of Hungary, residing at New York,

of which the following is a specification.

This invention relates to a telephone muf-.

fier comprising an attachment adapted for application to the mouth piece of the telephone transmitter whereby the voice of the telephone user is rendered inaudible to persons in the immediate vicinity.

The invention has for an object to provide a novel and efficient telephone muffler of simple and inexpensive construction which will act to break up and absorb transversely radiating sound waves and prevent also undesirable reverberation of the sound waves within the device.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawings and to the appended claims in which the various novel features of the invention are more particularly set forth.

Fig. 1 of the drawings is a face view, wlth certain parts in vertical section, of a telephone muffier constructed according to my invention.

Fig. 2 is a transverse vertical sectional view thereof, taken on the line 2+2 of Fig. l, the mufiler being here shown in position on the mouth-piece of telephone transmitter. l p

Fig.3 is a plan-view of the mufier.

Fig. i is fragmentary vertical sectional view showing a modified form of the muffler air passage. H w

Briefly speaking, in carrying out my invention, Iprovide a shell or casing which is adapted for mounting on the mouthpiece of a telephone receiver and into which the voice of the person telephoning is directed, this casing containing devices whereby the sound waves which spread out laterally are. absorbed and broken up.

- In the present embodiment of the invention the casing 10 is of elliptical shape as H I site face walls of this casing in the county of New York and State of. New York, have invented certain new and useful Improvements in Telephone Mufflers,

seen in face view with fiat face walls and is preferably made of aluminum. The oppoare provided with openlngs 11 and 12, the opening 12 in the rear wall corresponding in shape and area to the end of the transmitter mouthpiece wlth which it registers. In Fig. 2 of the drawings I have indicated my improved muflier in position upon a telephone, the mouthpiece being indicated at 13 and the transmitter body at 14. The openings 11 and 12 are preferably located midway between opposite ends of the casing 10 and toward the top side thereof. Surrounding the frontopening 11 is a forwardly projecting flange 15 which is suitably shaped to closely engage the lips of the user for the purpose both of preventing escape of the voice and entrance of foreign sounds. As a sanitary precaution I preferably provide a removable mouthpiece 16, of celluloid or the like, which fits on the flange 15 and can be readily applied or removed, being held in place by compressing its inner end, which is pro vided with slots 17, within the opening 11. To mount the device on the transmitter mouthpiece 13 I provide on the rear wall of the casing 10, and suitably. spaced around the opening 12, a number of spring clips 18 which engage over the mouthpiece 13.

To absorb the sound, and prevent undesirable reverberation of the sound waves in the casing 10, I provide in the latter suitably arranged sound absorbent material which is preferably of a foraminous nature such as felt or the like. This material may comprise a series of spaced strips 20 which extend around the bottom and sides of the shell as in Fig. 1 and are arranged to present openings 21 between one edge thereof and the adjacent face wall of the casing, the openings of adjacent strips being at opposite edges thereof thus providing a tortuous transversely directed air passage with felt walls leading outward from the central compartment of the easing into which the voice is projected. The term transversely directed is here used to indicate a passage leading in a general direction transversely to the path of the sound waves passing directly from opening 11 to opening 12. In addition to the above strips 20 I preferably provide an outer felt strip 22 which fits closely within the peripheral wall of the casing, this wall preferably being formed with small perforations 22-3 closely spaced throughout the bottom and ends thereof, but omitted on the top.

By providing the above arrangement the transversely directed sound waves are ade quately broken up and mullied any sound that may issue being in the form of a low and indistinct murmur entirely unintelligible to persons in the immediate vicinity, while at the same time any air compression or reverberation within the casing sufficient to interfere with the proper action of the transmitter diaphragm is prevented.

The same absorbing strips may be placed angularly in casing as at in Fig. 4, so as to form angular cross-sectioned air passage as 21, or air passages of any other suitable form.

\Vhile I have shown and described a pre ferred embodiment of my improved telephone mul'l'ler it is to be understood that I do not limit myself to the precise construc tion herein disclosed, and the right is reserved to all changes and modifications coming within the scope of the invention as defined in the appended claims.

Having thus described my invention what I claim as new and desire to protect by Letters Patent of the United States is as follows:

1. A telephone muffler comprising a casing adapted for application to a transmitter and having entrance and exit openings on opposite sides for the sound waves, and sound absorbent material in said casing comprising a series of parallel strips partially surrouiuling the space between said openings arranged to present a tortuous transversely directed air passage, the wall of said casing toward which said passage leads being formed with a plurality of small perforations spaced over a comparatively large area thereof.

2. A telephone muffler comprising a casing adapted for application to a transmitter and having, entrance and exit openings on opposite sides for the sound waves, and sound absorbent material in said casing arranged to present a tortuous transversely directed air passage, the wall of said casing toward which said passage leads being formed with a plurality of small perforations, and a strip of foraminous sound absorbent material lining said wall.

3. A. telephone muflier comprising a casing adapted for application to a transmitter and having entrance and exit openings on oppo site sides for the sound waves, and sound absorbent material in said casing comprising a series of parallel strips partially surrounding the space between said openings arranged to present a tortuous transversely directed .air passage, said sound absorbent material comprising a series of parallel strips spaced a short distance from one another, and having a staggered relation with respect to each other, the wall of said casing toward which said passage leads being formed with a plurality of small perforations spaced over a crnnparatively large area thereof.

4. A. telephone muffler comprising a casing adapted for application to a transmitter and having entrance and exit openings on opposite sides for the sound waves, and sound absorbent material in said casing arranged to present a tortuous transversely directed air passage, said sound absorbent material comprising a series of parallel strips spaced a short distance from one another, and having a staggered relation with respect to each other, the wall of said casing toward which said passage leads being formed with a plurality of small perforations, and a strip of foraminous sound absorbent material lining said wall.

5. A telephone nuifl'ler comprising a casing of elliptical shape in face view and having flat face walls presenting sound inlet and outlet openings, a series of felt strips arranged in parallel relation in said casing and extending from one face wall toward the other, and staggered with respect to one another, the peripheral wall of the casing being formed with small perforations, and a. felt lining covering the inner face of said peripheral wall.

(3. A. telephone mul'llcr comprising a casing of elliptical shape in face view and having flat face walls presenting sound inlet and outlet openings, a series of felt strips arranged in parallel relation in said casing and extending from one face wall toward the other, and staggered with respect to one an other, the peripheral wall of the casing being formed with small perforations, and a felt lining covering the inner face of said peripheral wall, and a plurality of spring clips on said casing for securing the same on the mouthpiece of the telephone.

7. A telephone muffler comprising a casing of elliptical shape in face View and having flat face walls presenting sound inlet and outlet openings, a series of felt strips arranged in parallel relation in said casing and extending from one face wall toward the other, and staggered with respect to one another, the peripheral wall of the casing being formed with small perforations, and a felt lining covering the inner face of said peripheral wall, the sound inlet opening being provided with an enclosing flange shaped to fit the mouth of the user.

8. A telephone muffler comprising a casing of elliptical shape in face view and having flat face walls presenting sound inlet and outlet openings, a series of felt strips arripheral wall, the sound inlet opening being ranged in parallel relation in said casing provided with an enclosing flange shaped to and extending from one face wall toward the fit the mouth of the user, and a removable 10 other, and staggered with respect to one anmouthpiece member fitting in said flange.

5 other, the peripheral wall of the casing being In testimony whereof I have aflixed my formed with small perforations, and a felt signature.

lining covering the inner face of said pe THEOBALD BENEDICT. 

